Q: First back up

Buy the ethernet usb adapter or if you are rich buy the thunderbolt ethernet adapter apple sell so you can get reasonable backup speeds from their MBA and MBPr without ethernet ports.

Every computer needs ethernet.. I consider one of the above adapters essential given the lame excuse that the port would not fit... when did it ever stop apple from designing a new port.

Plug it into the TC and turn off wireless on the laptop.

Once you have access to the TC, via ethernet you can do the backup in complete isolation to the network.

Or if you want to keep using internet, then have the TC plugged into the main router by ethernet and ethernet to the laptop..

TC should be in router mode if you have only a modem or in bridge if you have a modem / router.

Generally just do it in isolation.. it takes overnight at most generally.

If you have your TC in some mode that doesn't work, reset it.. the TC will go back to router mode.. You can then ignore all the errors and just do the backup. No reset will harm the files on the TC hard disk.

Once you finish the first backup go back to wireless.

Are you using an adapter?

Make sure the drivers are correctly loaded for it and it gets an IP address.

1. I reset my TC and linked the Ethernet cable to the WAN port on the TC

Must use LAN port .. not WAN.

2. Unplugged the TC and restarted the laptop (again without wifi) and connected the Ethernet to one of the LAN ports tried to set up the TC again the apt utility could not c any airport base stations and therefore could not  select it

This is the point you need to work on the problem.

Does the ethernet connectivity led come on.. on the TC.. whenever you plug in an ethernet a little LED comes on the port.. if it fails the ethernet cord or dongle isn't working.

You need to fix this. No connectivity no connection.

If you have connectivity is the computer getting an IP address from the TC.. make sure it is set to auto dhcp and if it still fails then the dongle drivers need patching, fixing or getting rid of.

Yeah.. well that happens..

Simply reset the TC. No reset will delete stuff from the hard disk.

The airport utility is great when it all works but unfortunately is less than straightforward otherwise. Personally I use 5.6 utility even on Mountain Lion because it is easier IMHO to set things the way I want them .. than the way Apple automates it, over which you have no control.

You can load 5.6 utility into ML using the following trick. (see below).

Set all wireless names to SMB standard.. short, no spaces and pure alphanumeric.

Lock the wireless channels if you continue to have problems.

Or do the full reset. And simply start over the TC setup.

How to load 5.6 into ML.

1. Download 5.6 for Lion.

http://support.apple.com/kb/DL1482

Click to open the dmg but do not attempt to install the pkg.. it won't work anyway.

2. Download and install unpkg.

http://www.timdoug.com/unpkg/

Run unpkg on the desktop.. it is very simple.. drag the AirPortUtility56.pkg file over to unpkg.. and it will create a new directory of the same name on the desktop.. drill down.. applications utilities .. there lo and behold is Airport utility 5.6 .. drag it to your main utilities directory or just run it from current location.

You cannot uninstall 6.1 (now 6.2 if you updated) so don't try.. and you cannot or should not run them both at the same time.. so just ignore the toyland version.. the plastic hammer.. and start using 5.6.. a real tool.

For screen shots see this post.

https://discussions.apple.com/thread/4668746?tstart=0

Not WAN.. you must be plugged into LAN port.

Do a full factory reset of the TC.

Hold in reset button, then power on the TC using your third arm.. keep holding reset in all the time.. using your first and second arms. (easy if you have a friend to help). Wait until the front LED flashes rapidly.. then release the reset.. about 10sec.

Do this in complete isolation. Ethernet plugged into LAN port only.

Then setup the TC wireless correctly.